We demonstrate that the exchange of zeolitic Brønsted acid sites (BASs) with cations from metal oxides plays a pivotal role in the propagation of hydrocarbon pools (HCPs) during CO₂ hydrogenation. We probed the likelihood of In₂O₃, ZnZrO_x, and Cr₂O₃ migration and their cation exchange with BASs of a silicoaluminophosphate, SAPO-34, by integrating them at nanoscale proximity (∼1,400 nm). Analysis with NH₃ temperature-programmed desorption and transmission Fourier transform infrared spectroscopy showed ion exchange of BASs with In^δ+ and Zn^δ+ but not for Cr^δ+. We measured the C₃/C₂ hydrocarbon ratio (indicating relative propagation of olefin to aromatic cycles) and paraffin-to-olefin ratio, which revealed that In^δ+ species inhibited HCPs inside the channels of SAPO-34, while Zn^δ+ species enhanced hydrogen transfer and secondary hydrogenation. Combining reactivity data with occluded hydrocarbon analysis and ¹³C solid-state nuclear magnetic resonance spectroscopy, we show that ion-exchanged species affect HCP propagation. Overall, our work provides insights for the rational integration of bifunctional catalysts.

中文翻译：

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与沸石酸位点的金属阳离子交换调节 CO2 加氢过程中烃库的繁殖


我们证明，沸石 Brønsted 酸位点 （BAS） 与金属氧化物阳离子的交换在 CO₂ 加氢过程中碳氢化合物库 （HCP） 的繁殖中起着关键作用。我们通过在纳米级接近 （∼1,400 nm） 整合它们，探测了 In₂O₃、ZnZrO_x 和 Cr₂O₃ 迁移的可能性及其与硅铝磷酸盐 SAPO-34 的 BAS 的阳离子交换。使用 NH₃ 程序升温解吸和透射傅里叶变换红外光谱分析显示 BAS 与 In^δ+ 和 Zn^δ+ 的离子交换，但 Cr^δ+ 没有。我们测量了 C₃/C₂ 烃比率（表明烯烃与芳烃循环的相对传播）和石蜡与烯烃比率，结果表明 In^δ+ 物种抑制了 SAPO-34 通道内的 HCP，而 Zn^δ+ 物种增强了氢转移和二次氢化。将反应性数据与封闭碳氢化合物分析和 ¹³C 固态核磁共振波谱相结合，我们表明离子交换物质会影响 HCP 的传播。总的来说，我们的工作为双功能催化剂的合理整合提供了见解。